Study For PET Based On Monte Carlo Simulation

Positron emission tomography?PET?is an advanced medical imaging device,which has important application value in the fields of oncology,neurology,cardiovascular science,and drug development.NEMA NU 2-2012 is a performance test standard for PET formulated by the American Electrical Manufacturers Association.GATE is a Monte Carlo simulation tool developed for nuclear medicine instruments by the open GATE collaboration.In this paper,the GATE was used to simulate the GE Discovery MI PET/CT according to the NEMA NU 2-2012standard.The research is mainly divided into three parts.First,the three top commercial PET of GE Discovery MI,Philips Vereos and Biograph Vision were simulated in GATE,the simulation sensitivity and scatter fraction were obtained by analyzing the simulation data.The simulation values were compared with the experimental values in the literature to verify the reliability of the simulation of the PET system.Second,on the basis of reliable modeling,the effects of different axial FOV on sensitivity and scatter fraction are studied.The method is to gradually increase the axial length of these three PET detectors until about 2 m to obtain the sensitivity and scatter fraction of each axial length.Third,the effect of different crystals on sensitivity and scatter fraction was studied.Taking the initial axial length as the prototype and other conditions unchanged,the effects of six different crystal materials including LYSO,LSO,GSO,YAP,Ce Br₃and Lu AP on sensitivity and scatter fraction were simulated.The results show that the PET model constructed by GATE in this paper agrees with the experimental measurements in the literature in terms of sensitivity and scatter fraction,which illustrates the reliability of the simulation results.With the increase of the axial length,the sensitivity also increases,but this increase is non-linear,and the most obvious change in a certain length,the most significant change in the corresponding axial length of different types of PET is also different.The axial length has no significant effect on the scatter fraction.Among the six different crystal materials,Lu AP has the highest sensitivity,LSYO and LSO crystals behave similarly,and YAP crystals have the lowest sensitivity.The paper studied the effects of different axial length and crystal material on performance parameters such as sensitivity and scattering fraction,which is positive for further improvement of PET performance and reduction costs of research and development.